1. Field of Invention
This invention relates to cavities for manipulating electromagnetic energy. Specifically, the present invention relates to resonant cavities and accompanying systems.
2. Description of the Related Art
Resonant cavities are employed in various demanding applications including lasers and optical filters. Such applications demand compact cost-effective resonant cavities that exhibit minimal optical losses.
Conventionally, resonant cavities are implemented via Fabry-Perot etalons, which are resonant cavities formed between two parallel facing partially reflective mirrors. Light is typically input perpendicularly through the backside of one mirror. Light resonating between the mirrors may exit the etalon through the front side of the opposing mirror.
To achieve a desired transmission profile with very narrow peaks and minimal losses, these so-called Fabry-Perot resonant cavities require highly reflective smooth parallel mirrors with low absorption coefficients. Otherwise, power loss due to the walk-off effect and absorption may be problematic. The walk-off effect occurs when mirror misalignments or surface defects cause electromagnetic energy oscillating between the mirrors to exit through sides of the resonant cavities.
Stringent requirements for Fabry-Perot etalons increase the price and design complexity of systems employing the etalons. For example, tunable optical filters may employ Fabry-Perot etalons, which are strategically angled relative to input electromagnetic energy to alter etalon output spectral characteristics. Unfortunately, the walk-off effect causes such filters to be prohibitively lossy for many applications. Furthermore, Fabry-Perot etalons typically exhibit resonance at discrete wavelengths only, which limits applicability of the etalons.
Hence, a need exists in the art for an efficient resonant cavity that mitigates parallelism, smoothness and other resonant cavity requirements; that eliminates walk-off of electromagnetic energy; and that supports resonance at a continuous range of wavelengths. There exists a further need for various systems employing the unique resonant cavities.